Automatic fuel regulator



June 1932. c, sTOKES 1,861,725

AUTOMATIC FUEL REGULATOR Filed Oct. 19, 1926 5x 1 JUNE 1:-II/IIIIIIIII/l/ IN V EN TOR.

Patented June 7, 1932 UNITED STATES PATENT OFFICE CHARLES LAWRENCESTOKES, 013 LOS ANGELES, CALIFORNIA, ASSIGNOR TO CURTIS B. CAMP,TRUSTEE, 0F GLENCOE, ILLINOIS AUTOMATIC FUEL REGULATOR Application filedOctober 19, 1926. Serial No. 142,761. E l S S U E My invention relatesto improvements in automatic fuel regulators for governing the supply offuel to an internal combustion engine.

The principal object of my invention is to provide a carburetor forinternal combustion engines which will give the optimum proportions offuel and air to the engine for carbureting the same in accordance withvarying temperatures of the engine.

Another object of my invention, is to provide a. carburetor for aninternal combustion engine so that the same may be started and operatedby proper carburetion to the end that no manual choking, or priming, isnecessary, the carburetion depending solely on functions of the engineitself, i. e., depending on the degree of vacuum in the engine and itstemperature.

Another object of my invention is to provide a thermostaticallycontrolled carburetor.

Another object is to provide a carburetor of cheap and efficientstructure.

This application is a continuation in part of my co-pendingapplications, S. N. 67864, filed Nov. 9, 1925 and S. N. 106,012, filedMay 1st. 1926.

Referring to the drawing in which the same numbers indicate like parts:

Fig. 1 is a vertical sectional view of a carburetor embodying myinvention.

Fig. 2 is a view showing the carburetor in its relation to an internalcombustion engine.

Fig. 3 is an enlarged sectional view of part of Fig. 1 at startingpositions.

Fig. 4 is a transverse sectional view of part of Fig. 2 showing thethermostat and the mounting therefor.

Fig. 5 is a sectional detail of part of Fig. 4.

Fig. 6 is an alternative construction for partof Fig. 4.

F ig. 7 is an enlarged fragmentary sectional view of the dischargenozzle.

Referring to Fig. 2, an internal combustion engine 1 is shown having anexhaust pipe 2, an inlet pipe 3 and a carburetor 4 attached to theintake pipe 3, the air intake 5 of carburetor 4 being attached by a hotair pipe 6 to a stove T surroumling exhaust pipe 2. A block 5 isfastened to exhaust pipe 2 and supports a bi-metallic thermostat 9 forcontrolling at certain times the operation of carburetor 4 through asuitable mechanism 10. Carburetor 4 may be supplied with liquid fuel, byany well known feed system, through a pipe 11. I

Referring to Figs. 1 and 3, carburetor 4 includes an air intake 5 and amixing chamber 12 of the usual circular cross-section, mixing chamber 12containing a large venturi 13 and a small venturi 14, the outlet of thelatter being adapted to reach the throat of large venturi 13. Liquidfuel supplied through pipe 11 passes through a valve (not shown) to afuel reservoir 15, the liquid lever therein being controlled by a float16 attached to the valve in a well known manner. Reservoir 15 has acover 17 and is open to atmosphere through a vent 18.

Liquid fuel from reservoir 15 passes through a passage 19 to the lowerpart of a well 20 of circular cross-section, divided above the passage19 into two parts by means of a plug 21 supporting a'pipe 22 in suchfashion that liquid fuel will rise to static level interiorly of tube22. The bottom of well 20 is closed by a plug 23 having a fuelpassage 24therethrough and supporting therein a pipe 25 which passes through theinterior of pipe 22. Passage 24 is adapted to connect with a passage 26wherein is set a nozzle 27 concentric with a second nozzle 28, thedischarge of both nozzles being substantially at the throat of smallventuri 14 and slightly above the liquid level XX. A passage 29 suppliesnozzle 28 with liquid fuel and air from the upper part of well 20 andnozzle 27 has a small orifice 30 therein adapted to connect passage 29with passage 26.

Liquid fuel is supplied to the interior of tube 25 through an orifice 31and tubes 22 and 25 fit in recesses in the metal of carburetor 4 at theupper end of well 20, well 20 being open to atmosphere through a highspeed regulating valve 32 and at times through a port 44, as willpresently appear.

A throttle 35 is placed in mixing chamber 12 for the purpose ofcontrolling the main supply of liquid fuel and air to engine 1 and abovethe closing point of throttle 33 is placed an orifice 34 for connectingmixing chamber 12 with the interior of a casing 35 which may form anextension of the body of carburetor 4. In casing 35 a valve 36 isadapted to reciprocate, the same being reduced at one end to an orifice37 of predetermined size, the

. other end terminating in a threaded portion being controlled by theposition of valve 36 with respect to the discharge from tube 25 intocasing 35. Valve 36 is provided with an annular space 42 having atapered portion 43 which is adapted to connect the interior of wellthrough a passage 44 with an atmosphere port 45. The outer end of valve36 is squared to work through a guide 46 in order to maintain orifices39 and 40 in the proper relation to the discharge from tube and valve 41and casing is expanded at guide 46 to hold a spring 47 encircling theend of valve 36 and pressing against nut 38, there being a suitableclearance between nut 38 and the interior of casing 35. The expandedportion of casing 35 is open to atmosphere through ports 48 and thecasing has a threaded orifice 49 for the insertion of a pin or setscrew, or other locking means, for holding valve 36 in predeterminedposition when desired to make the starting apparatus inoperative.

On the outer end of casing 35 is threaded an extension 50 for guiding arod 51 which is adapted to be ,actuated by the movement of thermostat 9,responsive to the heat of engine 1, through a cup-shaped member 52within which a spring 53 fits closely for contacting with an enlargedhead 54 on rod 51, it being noted that spring 53 extends outside ofmember 52 to the end that a portion of spring 53 outside shall form aflexible contact having more or less universalmovementin case ofmisalignment, spring 53 being stiffer than spring 47.

Thermostat 9 is fastened to block 8 which is threaded into exhaust pipe2 and one end of block 8 is cut at an angle to receive the impact ofheated exhaust gases which pass through passage 58 in block 8 anddeflect the same to escape to atmosphere at times through a port 59controlled by the move ment of a valve 60 suitably fastened to member 52and adapted. to be actuated by the movement thereof, responsive to themovement of thermostat 9. It should he noted that clearance betweenvalve 60 and the walls of the passage 61 is allowed for equalizing thepressure on valve 60 until the same closes port 59.

An alternative construction, as shown as Fig. 6, illustrating thatmember 52 slides freely on the end of valve 60, the end of valve 60being threaded to receive a nut 62 interiorly of member 52 for holdingspring 53 therein and the end of 52 is now adapted to abut on the head54. This construction permits thermostat 9 to seat valves 60 and 36flexibly against the resistance of springs 47 and 53, it beingunderstood that, while rod 51- is shown as straight for straight linemotion, casing 50 may be curved and rod 51 may be wire as is Well knownin Bowden wire mechanisms.

The operation is as follows:

Referring particularly to Figs. 1, 2, 3, 4 and 5, if it be assumed thatengine 1 is at low temperature and very cold, thermostat 9 will becontracted to leave port 59 wide open and at this time a plurality ofthe orifices 39 will be in registry with the discharge from tube 25 andnone, or one, of the orifices 40 will be in registry with atmospherethrough valve 41, the position of orifices 39 and 40 being due to spring47 which has forced rod 51 and member 52, through the medium of spring53 into contact with thermostat 9, it being understood that there isalways contact of head 54 with spring 53.

Upon cranking engine 1 with throttle 33 closed, a high partial vacuum isdeveloped in chamber 12 on the engine side of throttle 33 which vacuumis applied through orifices 34 and 37 for elevating liquid fuel,standing at the static level XX. in pipe 25 and from the upper part ofwell 20 through orifice 30. The well 20 and pipe 25 comprise a reservoirof such capacity, together with the contents of passages 24 and 26 andwith liquid fuel flowing through orifice 30, that the column of liquidfuel in tube 25 will be maintained substantially solid so that under thestarting conditions described. there will be a very large proportion ofliquid fuel drawn through orifices 39 to the cylinders of engine 1 forpriming and starting the same, it being understood that during thecranking period, the resistance of spring 47 will be suflicient tomaintain valve 36 in substantially fixed position.

As soon as the very rich priming charge has been fired and the enginestarts to idle, there is a decided increase in vacuum in chamber 12 dueto increased piston speed, the throttle 33 remaining in the sameposition, and this sudden increase in vacuum causes valve 36 to movetoward chamber 12 a certain distance whereby one, or more, of theorifices 39 is shrouded in casing 35, thus reducing the richness of thepriming mixture to a rich mixture for operating engine 1.

Engine 1 will continue to operate and the hot exhaust gases will pass toatmosphere through exhaust pipe 2 and impinge on their way on the faceof block 8, whereby a portion of the hot gases is deflected throughpasfices 39, one or more of the orifices 40 are exposed to atmosphere,and thus the richness of the mixture is reduced in two ways; first, byactually cutting off the liquid supply through the shrouding of one ormore orifices 39, and secondly, by reducing the suction applied to theremaining orifices by the introduction of an increasing amount of airthrough orifices 40.

Upon the continued operation of engine 1, the same will finally reach anoptimum operating temperature whereby thermostat 9 will reach itsmaximum expansion and valve 36 will become seated in the end of casing35 over orifice 34, leaving only one orifice 39 for connecting theinterior of valve 36 with the discharge from pipe 26. This remainingorifice will be very small and will be used as an idling orifice atoptimum engine operating temperatures and the idling mixture may then beadjusted by means of valve 41.

As a general rule, the device is so proportioned that when idling oneend of the liquid column in nozzle 27, passages 26 and 24 and tube 25,will not come lower than the bottom of passage 26, the demand for liquidfuel through orifices 39 during the initial priming period, asdescribed, being suificient only to reduce the liquid level to thisextent and thereafter upon shrouding some of orifices 39, as described,the demand for liquid fuel through the remaining orifices may be morethan supplied through orifice 31 whereupon the liquid level in passage26 and nozzle 27 will gradually increase until it reaches the staticlevel X-X at which time fuel will be supplied only through the smallestand last orifice 39.

In this manner it will be seen that a very rich priming charge is firstsupplied to the engine and thereafter, as soon as the priming charge isfired, the richness of the mixture is cut down and gradually reduced tonormal as optimum engine operating temperatures are reached.

Now upon opening throttle 33 wide, a sudden drop in vacuum tosubstantially atmospheric pressure will ensue in chamber 12 to the endthat substantially at mospheric pressure will prevail Within valve 36,more particularly because the capacities of orifices 40 are muchgreaterthan that'of orifice 37, so that the column of liquid fuel beingheld up, as described, in tube 25, will drop and be forced from the topof nozzle 27 above the liquid level XX and this discharge of liquid fuelinto the air stream is accelerated by the sudden increase in vacuum atthe throat of venturi 14 due to the sudden increase in velocity of airresponsive to the sudden opening of throttle 33.

Engine 1 thereupon receives an acoeleratin g charge which will emptytube 25 and nozzle 27 and thereafter a proportion of the liquid fuel forrunning will be supplied through orifice 31 responsive to the suction atthe throat of venturi 14.

The sudden increase in suction at the throat of venturi l talso reactson nozzle 28 to withdraw liquid fuel standing in well 20 and thereafter,as soon as well 20 and nozzle 28 are emptied, the vacuum at the throatof venturi 14 will be applied through nozzle 28, orifice 30 and passage29 to the interior of well 20 and through a plurality of orifices 63 tothe interior of tube 22 for raising the li uid level therein and causinga flow of liquid uel through one or more of orifices 63 for supplyingengine 1 under varying conditions of load and speed,- it being notedthat orifices 63 are all above the liquid level XX, this being desirablein order that at starting periods there shall be no more liquid fuelsupplied to well 20 than what can pass through orifice 30.

With increasing, or decreasing, engine speeds, the vacuum at the throatof venturi 14 will vary, therefore varying the height of the liquidcolumn in tube 22 and thus varying the liquid fuel supply throughorifices 63 and this variation being solely due to variations in vacuumresponsive to the speed, or load, of engine 1. the same may be regulatedfor high speed work by means of regulating valve 32.

In addition. at starting periods. if it is desired to acceleratethermostat 9 being fully contracted, it will be noted that a sudden dropin vacuum in chamber 12 caused by sudden opening of throttle will notonly cause I the liquid column in tube 25 to drop and discharge asalready described but will permit a sudden recession of valve 36 foropening all of orifices 39 and this recession of valve 36 causesatmosphere to be cut off from the interior of well 20 through grooves42, 43 and passages 14 and 45. Thus in cold weather and under similarconditions of accelerating and operating, a greater or less degree ofvacuum will be automatically applied by the movement of valve 36 to theinterior of well 20 for causing an increased feed through orifices 63for high speed work when engine 1 is cold.

It will be noted that. block 8 may be cast integral withpipe 2. andcontains considerable metal. thus forming a reservoir for heat whereby,onstopping'engine 1 after thermostat 9 has reached maximum expansion theorifices 29 will be gradually uncovered only in proportion to that rate(if heat loss. Thus a proportionate priming charge will be supplied toengine 1, depending on its temperature, as well as a proportionateaccelerating and running mixture.

Thermostat 9 and block 8 may be shrouded by a cover (not shown) toreduce the rate of cooling.

Passage 58 is provided for giving a rather quick initial expansion tothermostat 9 and bringing block 8 rapidly up to temperature, as it isdesirable that a time element be involved whereby some of orifices 39should not supply liquid fuel for too long a period.

It will be noted that the vacuum for drawing liquid fuel up. andmaintaining the same for accelerating in, tube 25 is applied throughvalve 36 and casing 35 comprising passages for liquid fuel and air.Also, for good construction it is found that valve 36 should not bemoved more than three-eighths of an inch. this being advisable onaccount of the maximum desirable expansion of the bi-metallic thermostat9 which. if exceeded. causes undue stresses in the metal thereof andcauses the same to operate inaccurately.

At other positions of throttle beyond starting and accelerating. asdescribed. for varying speeds of engine 1 the supply of liquid fuel fromorifices 63 will vary according to the degree of vacuum at the throat ofventuri 14. but as already stated, orifices 63 should preferably beabove the level X-X so that there will be a gradual overlap and supplyfrom orifices 31 and 63. well 20 gradually filling through orifice 30when engine 1 is not in operation. although the carburetor is entirelyoperative if some of the orifices 63 are below the level X-X.

After the accelerating discharge from tube 25 takes place liquid fuel isdrawn through orifice 31 and a small amount of air through orifices 40and the idling orifice 39, valve 36 being at its innermost position dueto the action of thermostat 9. also air and liquid fuel will be drawnfrom well 20 through orifices 63 and/or passage 44 and valve 32 and thustwo separate columns of liquid fuel and air, or emulsions of fuel andair, will discharge from nozzles 27 and 28 to mix at the throat ofventuri 14. This action gives good atomization and carburetion.

Carburetor 4 may be used as a non-thermq statically controlledcarburetor simply by in serting a locking pin or set screw in orifice 49whereby valve 36 will be held in its innermost position. Valve 36 is afree fit in casing 35. Should there be a leak of fuel around valve 36through orifice 34 due to the engine vacuum. a groove 64 may be. cut invalve 36 for registering with an atmosphere port 65. when valve 36approaches its innermost position. so that air instead of liquid fuelwill be drawn into the mixing chamber 12 from around said valve.

It will be understood that valves 32 and 41 may be replaced by setorifices and also that upon opening throttle 33 wide, the reciprocationof valve 36 is governed by the difference in the strength of spring 47and thermostat 9 and may permit one or more of the orifices 39 toregister with the discharge from tube 25 so that atmospheric pressurethrough orifices 40 will have quicker access to the interior of tube 25for permitting the liquid fuel therein to drop more rapidly and supplynozzle 27.

lVhen the liquid fuel in tube 25 drops for sudden acceleration it isunderstood that the capacity of tube 25 is suflicient for the purpose ofproviding an accelerating charge over and above the amount whichnormally leaks back through orifice 31 and, as before stated, thedischarge from tube 25 is not only due to the head of liquid thereinover and above the liquid XX but is also due in part to the suddenincrease in vacuum at the throat of Veuturi 14 although the initialdischarge is believed to be solely due to the head of liquid in tube 25.

I claim:

1. In a carburetor, a mixing chamber, a throttle controlling the outletfrom the mixin g chamber. a liquid fuel reservoir, a well between themixing chamber and reservoir divided into two parts and supplied withliquid fuel from the reservoir. a liquid feed passage supplied from thewell having its ends discharging into the mixing chamber one on eachside of said throttle and a second liquid feed passage supplied from theupper part of the well and discharging into the mixing chamber.

The combination with an internal combustion engine of a carburetorhaving a mixing chamber, a throttle controlling the outlet from themixing chamber. a liquid fuel reservoir, a well between the mixingchamber and reservoir and supplied with liquid fuel from the reservoir.:1- liquid feed passage supplied from the well having its endsdischarging into the mixing chamber one on each side of said throttle.and means responsive to engine vacuum and temperature for controllingthe discharge from said passage.

3. The combination with an internal combustion engine of a carburetorhaving a mixing chamber, a throttle controlling the, outlet from themixing chamber. a liquid fuel reservoir. a well between the mixingchau1- her and reservoir divided into two parts and supplied with liquidfuel from the reservoir. a liquid feed passage supplied from thewellhaving its ends discharging into the mixing chamber one on each sideof said throttle. a second liquid feed passage supplied from the upperpart of the well and discharging into the mixing chamber and means tosuppl all to the second passage.

4. The combination with an internal co1ubustion engine of a carburetorhaving a mixing chamber. a throttle controlling the outlet from themixing chamber. a liquid fuel rcsc voir, a well between the mixingchamber and reservoir divided into two parts and supplied ill withliquid fuel from the reservoir, a liquid feed passage supplied from theWell having its ends discharging into the mixing chamber one on eachside of said throttle, a second liquid feed passage supplied from theupper part of the well and discharging into the mixing chamber, means tosupply air to said sec- 0nd passage, and means responsive to the enginevacuum to control said air supply.

5. The combination with an internal combustion engine of a carburetorhaving a mixing chamber, a throttle controlling the outlet from themixing chamber, a liquid fuel reservoir, a well between the mixingchamber and reservoir divided into two parts and supplied with liquidfuel from the reservoir, a liquid feed passage supplied from the wellhaving its ends discharging into the mixing chamber one on each side ofsaid throttle, a second liquid feed passage supplied from the upper partof the well and discharging into the mixing chamber, means to supply airto said second passage, and means responsive to the engine temperaturefor controlling said air supply.

6. The combination with an internal combusti on engine of a carburetorhaving a mixing chamber, a throttle controlling the outlet from themixing chamber, a liquid fuel reservoir, a well between the mixingchamber and reservoir divided into two parts and supplied with liquidfuel from the reservoir, a liquid feed passage supplied from the wellhaving its ends discharging into the mixing chamber one on each side ofsaid throttle, a second liquid feed passage supplied from the upper partof the well and discharging into the mixing chamber and means responsiveto engine vacuum and temperature for supplying air to the secondpassage.

7 The combination with an internal combustion engine of a carburetorhaving a mixing chamber, a throttle controlling the outlet from themixing chamber, a liquid fuel reservoir, a well between the mixingchamber and reservoir and supplied with liquid fuel from the reservoir,a liquid feed passage supplied from the well having its ends discharginginto the mixing chamber one on each side of said throttle, and meansactuated by engine temperature to supply air to said passage.

8. The combination with an internal oombustion engine of a carburetorhaving a mixing chamber, a throttle controlling the outlet from themixing chamber, a liquid fuel reservoir, a well between the mixingchamber and reservoir and supplied with liquid fuel from the reservoir,a liquid feed passage supplied from the well having its ends discharginginto the mixing chamber one on each side of said throttle, and meansactuated by engine vacuum and temperature to supply air to said passage.

Signed at Los Angeles, in the county of

